Dual PWM relay driver with diagnostics for functional safety system

    公开(公告)号:US11114842B1

    公开(公告)日:2021-09-07

    申请号:US16884318

    申请日:2020-05-27

    Abstract: A component includes first and second switches in series and connected between a power source and a coil of contacts of a safety relay. A first controller controls the first switch with a close signal that closes the first switch or a first PWM signal that opens and closes the first switch on each PWM cycle. A second controller controls the second switch with a close signal that closes the second switch or a second PWM signal that opens and closes the second switch on each PWM cycle. A PWM sensing circuit connected to the coil sends a sensed PWM signal to an input of the first and second controllers. The first controller sends the first PWM signal while the second controller sends a close signal and vice-versa. The controllers verify that the received PWM signal matches the sent PWM signal.

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